deletions | additions       diff --git a/begin_equation_frac_d_dA__.tex b/begin_equation_frac_d_dA__.tex  index 75e60f7..9fab196 100644  --- a/begin_equation_frac_d_dA__.tex  +++ b/begin_equation_frac_d_dA__.tex 
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\begin{equation*}  \frac{d}{d\mathcal{A}}\int_\mathcal{G} \rho dV = - \int_{\partial \mathcal{G}}f \mathcal{G}}\mathcal{f}  \cdot n \mathcal{n}  \,dS\nonumber \end{equation*}